Electrical testing apparatus for fluid-pressure engines



July 12, 1927. 1 635,980

F. W. HIGHFI ELD ET AL ELECTRICAL TESTING APPARATUS FOR FLUID BRESSURE ENGINES Filbd Nov. 10. 1924 I s wfj Patented July 12, 1927.

UNITED; STATES,

PATENT OFFICE.

- LAND, ASSIGNORS TO THE TRY, ENGLAND.

HIGHFIELD ELECTRICAL COMPANY LIMITED, 0F COVEN- ELECTRICAL TESTING gram es roarL m-ranssonn ENGINES.

Application filed November 10, 1924, seri iNo. 749,697, and in Great Britain December a, 1923.

motor vehicles are manufactured in large quantities.

The object of the invention is a5 enable the conditioning and testing operations to be performed more expeditiously and advantageously than heretofore and without high- 1y skilled supervision. j

The invention comprises the employment of a dynamo-electric machine towhich the engine is coupled, the said machine being capable of operating as a motor or generator, together with means whereby the conditioning (or running-in) operations can be carried out in two or more stages, and finally the engine can be run under its own power. I i i The invention also comprises the employment in the circuit of the dynamo-electric machineof indicating and controlling apparatus as hereinafter described.

The accompanying diagram illustrates one manner of carrying the invention into efiect for the running-in and testing of petrol engines.

Referring to the diagram, 11 is the dynamo-electric machine to which the engine is coupled. The machine is compound wound, the series winding being indicated by b and the shunt winding by c. i In conjunction with b is a regulating resistance (Z, and in conjunction with c is a regulating resistance 6. The parts c and a may be combined with a shunt discharging circuit containing a suitable resistance 7 for preventing excessive sparking when the supply circuit is broken. A main or isolating switch is employed and indicated by g. I

In series with the machine are arranged a watt-meter w of the dynamometer type with central zero, an overload relay i, a minimum current relay j, a differential relay ]c, a switch Z, and a maximum power relay m. In conjunction with the system is the machine a is operating as a motor.

also preferably arranged an additional or local circuit n containing a switch 0. This circuit is used when the engine is being adjusted to run under its own .power. 7

Push buttons andcontactors are prefera- 'bly employed to bring the different parts of the system into operation, and in conjunction with the system are arranged suitably coloured lamps or other convenient indie at ing devices. An electrical or other speed indicatormay be added.

Startingwith anengine coupled to the dynamoelectricmachine a, the attendant,

closes the switch 9 and presses a button which causes the switch or contactor l to be closed? The machine now functions as a motor, and the adjustments are such that the'engine isdriven at a slow speed. In this-conditionjthe greater part or all of, the resistance (Z would be in action. The power consumed is indicated by' the. watt-meter w, and the differential relay 7c closes a cir- V 'cuit containing, for'example, a red lamp 8 or other indicating device showing that i If the current taken by the motor is excessive, owing to excessive resistance to rotation in the engine, the overload relay i comes into action and causes the current supply circuit to be opened. If the current required is normal, the motor continues to rotate at a relatively slow speed, but gradually, as the working parts of the engine become easier, the current necessary to drive the motor de creases in value, and eventually (under ordi-- nary conditions) reaches a, predetermined minimum value. The minimum current relay y then comes into action and closes a circuit containing, for example, a white lamp to or other indicating device which announces to the attendant that the first stage of the run ning-in process has been completed. The attendant then operates a press button whereby the resistance (Z and the series field winding 7) are put out of action, causing the .motor to be driven at a predetermined higher speed. The current required by the motor thereupon increases, the white lamp "w or other indicator ceases to function, and

the engine enters upon the next (and usually final) stage of the running-in process. As before the current falls as the engine becomes easier, until eventually it again reaches the lower limit and the lamp or 

